The present invention relates to an electronic system and an operating method thereof, and particularly to a technique effective in compensating for non-linearity of an AD conversion unit and non-linearity of a DA conversion unit in an electronic system including the DA conversion unit and the AD conversion unit.
The following Patent Document 1 describes an A/D converter called a background digital correction type A/D converter. The background digital correction type A/D converter includes a main A/D conversion unit which performs a high-speed A/D conversion operation with low precision, a reference A/D conversion unit which performs high-resolution A/D conversion at low speed, and a digital correction unit which generates a final digital output signal from a digital signal of the main A/D conversion unit and a digital signal of the reference A/D conversion unit.
The following Patent Document 2 and Non-patent Document 1 describe an A/D converter called a foreground digital correction type A/D converter. The foreground digital correction type A/D converter includes a main A/D conversion unit, a reference D/A conversion unit, a switch, a foreground calibration unit, and a digital output generation unit. During a calibration operation period, a calibration digital signal is converted into a calibration analog signal by the reference D/A conversion unit, and the calibration analog signal is supplied to an input terminal of the main A/D conversion unit via the switch. A digital signal generated from an output terminal of the main A/D conversion unit is supplied to an input terminal of the digital output generation unit, the calibration digital signal and a final digital output signal of the digital output generation unit are supplied to the foreground calibration unit, and an output signal of the foreground calibration unit is supplied to a control input terminal of the digital output generation unit. As a result, the digital output generation unit is controlled by the output signal of the foreground calibration unit so that the calibration digital signal supplied to the foreground calibration unit and the final digital output signal of the digital output generation unit agree with each other.
[Patent Document 1]
    Japanese Unexamined Patent Publication No. 2009-130444[Patent Document 2]    Japanese Unexamined Patent Publication No. 2009-159415[Non-Patent Document 1]    Takashi Oshima et al, “23 mW 50-MS/s 10-bit Pipeline A/D Converter with Nonlinear LMS Foreground Calibration”, 2009 International Symposium on Circuits and Systems, PP. 960-063